The gender pay gap by which women earn significantly less than men during their careers begins early in childhood with boys receiving 20% more pocket money than girls, according to a report.

Not only do girls receive less money, they are allowed less financial independence; they are less likely to receive regular payments than boys, and are more dependent on others to buy items for them and manage their money on their behalf.

Whereas boys aged five to 16 receive an average of £10.70 per week from either pocket money, payment for chores or paid work, girls of the same age receive just £8.50, and the gap widens as the children get older, the findings suggest.

According to the report by market research agency Childwise, between the ages of 11 and16 the gap grows to 30%, with boys receiving an average weekly income of £17.80 and girls of the same age lagging behind with £12.50.

The report, which is conducted annually and is based on online surveys with 2,000 schoolchildren, reveals not only the inequality between boys and girls in terms of hard cash, it also indicates the different messages parents give their sons and daughters about money and financial management.

While boys are more likely to be given regular cash payments, giving them financial autonomy from an early age, the survey findings suggest parents of girls are more likely to keep hold of their daughters’ money, then hand it over when it is required.

“The data points towards an early gender imbalance in the way parents educate their children about money matters and financial independence,” said Childwise’s research manager, Jenny Ehren.

“Boys are more likely to be entrusted with regular cash payments, while girls are more reliant on other people buying them items, or managing money on their behalf.

Girls’ pocket money is more likely to be supplemented by parents buying expensive items such as clothes and footwear, as well as much cheaper purchases including toiletries and makeup. “The value of these purchases almost certainly helps to bridge the income gap between boys and girls,” said Ehren, “but the approach to managing finances is noticeably different.

“Children pick up gender clues all around them, some subtle, and some not so subtle. The challenge for parents is to avoid inadvertently perpetuating these gender divisions themselves, and to help children learn the skills needed to be a confident and independent adult.”

According to the latest statistics, the current overall gender pay gap for full-time workers is 13.9%. Sam Smethers, the chief executive of the Fawcett Society, which campaigns for pay equality, responded to the report’s findings with irony: “Prepare your daughter for working life – give her less pocket money than your son.

“It seems that the gender pay gap starts at home. These figures reveal that we undervalue girls from a very early age. What chance do they have at work?”

Elsewhere in the wide-ranging report, findings suggest there has been a rise in the proportion of girls aged 15 and 16 taking part in sport at school, with three in four now participating, compared with just half in 2015. Smethers welcomed the increase, saying: “Perhaps an indication of the success of Sport England’s This Girl Can campaign and a legacy of the Olympics?”

Looking at children’s and young people’s use of mobiles, 31% said they had to check their devices every few minutes, rising to 42% of 17- to 18-year-olds, while a quarter of nine- to 16-year-olds admitted to turning off or getting round parental safety controls online. Even among children at primary school, the survey found that mobiles were taking over from tablets.

“The mobile phone is increasingly becoming a preferred go-to multimedia gadget for children overall,” said the Childwise research director, Simon Leggett. “For primary-aged children particularly, exposure to what a tablet can offer has left them wanting more, especially when they are outside the home.”